Case Study: How KarmaKrew Stayed Online During a Brutal A2S DDoS Campaign

(Thanks to VxShield: The Most Advanced DayZ Anti-DDoS Stack on the Planet)

🧵 The Backstory

KarmaKrew isn’t your average DayZ server. It’s one of the most recognized names in the modded PvP and RP space — known for brutal firefights, deep storylines, and high-stakes raids that can stretch on for hours. Their Discord has more drama than a Netflix reboot and a more active playerbase than half the survival games on Steam.

So when a coordinated DDoS campaign targeting DayZ servers started rolling through the community in early 2025, KarmaKrew was a prime target.

What the attackers didn’t know?

KarmaKrew runs behind our VxShield stack — and we were more than ready.

🧨 The Attack Vector: Weaponizing A2S Queries

Here’s the part most hosts don’t understand (or want to avoid):
The A2S query protocol, originally built to support the Steam server browser and launcher tools, has quietly become one of the most abusable DDoS vectors in modern multiplayer games.

In simple terms, the A2S protocol allows clients to ask:

• “What’s your server name?” (A2S_INFO)
• “How many players are connected?” (A2S_PLAYER)
• “What’s your server rules/config?” (A2S_RULES)

These are lightweight UDP requests. But:

• They’re stateless and unauthenticated
• They bypass TCP handshakes
• They can be spoofed with fake IPs
• They’re cheap to send and expensive to handle, especially in volume

In an A2S DDoS campaign, attackers blast these queries by the millions, often using spoofed IPs. The result?

• Server CPU maxes out processing packet floods
• Players lag or get disconnected
• Steam browser visibility drops — server looks empty or offline
• Player trust erodes fast

⚙️ What Makes VxShield Different?

While other hosts panic or apply basic rate-limiting (which breaks legit players), VxShield handles this at scale, 24/7, automatically — with no impact to player experience.

Here’s how we built VxShield to stop A2S DDoS attacks cold:

🔐 1. Always-On A2S Caching

We cache Steam queries 24/7, not just during attacks. Most hosts only “rate-limit” when things get bad — by then, it’s too late.

• A2S_INFO and A2S_RULES are cached intelligently with low TTLs
• A2S_PLAYER is refreshed dynamically to reflect live player data without spamming the origin
• Requests are served from edge memory, never touching the game server unless absolutely necessary

🛡️ 2. Smart Packet Inspection

VxShield understands the structure of valid A2S queries:

• We block malformed payloads and invalid sequence flags
• We detect spoofed origin IPs using deep UDP heuristics
• We reject A2S queries with unrealistic request intervals (anti-bot logic)

🌐 3. Anycast + Edge Filtering

All protected servers, including KarmaKrew, benefit from anycast routing:

• Traffic is absorbed and filtered before it ever hits the datacenter
• Attack packets are dropped at edge POPs nearest to the source
• Global latency stays low — no round-trips to a central firewall

🔄 4. Adaptive Auto-Tuning

VxShield learns from traffic patterns in real time:

• Adjusts cache TTLs based on query rates and player churn
• Changes filtering aggressiveness during attacks without human input
• Can differentiate between Steam browser pings and malicious bursts

✅ The Results: KarmaKrew? Untouched.

During the peak of the A2S DDoS storm:

• KarmaKrew experienced zero downtime
• Not a single player was disconnected due to server overload
• Steam browser presence remained 100% consistent
• Their Discord? Quiet. Just in-game drama as usual

Why? Because they had VxShield, and most others didn’t.

Other servers reported:

• Vanishing from server browsers
• Exploding support tickets
• Players assuming they'd been "admin wiped" or banned
• Lost playerbases that never came back

🧠 Why Other Hosts Can’t Handle It

Most providers either:

• Use off-the-shelf game filters that aren’t DayZ-aware
• Rely on generic UDP mitigation, which doesn’t distinguish A2S from legitimate traffic
• Disable A2S traffic entirely during attacks — breaking server visibility
• Or worst of all… they just let it through and hope for the best

And let's be honest: your server can have the best base builds in the world, but if no one can find it or connect to it, what’s the point?

⚡ Want your server protected like KarmaKrew?

Explore VYKIX plans or Get in touch with us — we'll help you stay online, always.